#include "apue.h"

Sigfunc *
signal(int signo, Sigfunc *func) {
	struct sigaction act, oact;

	act.sa_handler = func;
	sigemptyset(&act.sa_mask);
	act.sa_flags = 0;

	if (signo == SIGALRM) {
	#ifdef SA_INTERRUPT
		act.as_flags |= SA_INTERRUPT;
	#endif
	} else {
		act.sa_flags |= SA_RESTART;
	}

	if (sigaction(signo, &act, &oact) < 0) {
		return (SIG_ERR);
	}

	return oact.sa_handler;
}
